What a replica IW371745 is
Answer first: the replica IW371745 is a copy of the IWC Portugieser Chronograph 41, a 41mm stainless steel watch with two subdials stacked at 12 and 6. The better copies get the case silhouette, the dial printing, and the subdial spacing close enough that someone across a table will not notice. They are still copies. The movement inside is not IWC's in-house Calibre 69355, the decoration you see through the back is cosmetic, and no factory stands behind it with a service network.
Four things decide whether a specific example is worth owning: case thickness, dial printing, subdial layout, and how the chronograph starts, stops, and resets.
Case and proportions
The genuine reference measures 41mm wide and about 13mm thick, with long lugs that make it wear bigger than the number suggests. Most replicas land within a millimeter on width. Thickness is where they drift, often by half a millimeter up to 1.5mm, because the movement and its spacer sit taller than the original's.
What I look at:
- Lug-to-lug length. Compare it against published specs, not memory.
- Caseback height. A bulging back is the fastest giveaway on the wrist.
- Finishing transitions. The original mixes brushed flanks with a polished bezel and lug bevels, and the line between them should be crisp.
- Pushers and crown. They should sit level, thread smoothly, and not wobble.
The movement question
Almost every replica of this reference runs a modified 7750-family automatic. That layout works because the third counter is removed, leaving the 30-minute totalizer at 12 and small running seconds at 6, which matches the real dial. Newer batches sometimes ship with a decorated clone that copies the IWC rotor and bridge shapes.
Function matters more than engraving. Press the top pusher and the chronograph should start with a firm click, not a mush. Press the bottom one and the central hand should snap back to zero in one motion and stay there. If it lands near 11:59 or needs a second press, send it back.
Power reserve runs about 40 hours or a bit more. It is a mechanical watch, so treat it like one.
Dial, hands, and print
The Portugieser dial looks simple, which is exactly why small errors show. The railway minute track should be thin, even, and unbroken where it meets the subdial rings. Applied numerals should have straight edges and sit flush to the surface. The printed signature and the International Watch Co line should stay sharp under a loupe rather than going fuzzy at the edges.
Hands are another checkpoint. The leaf-shaped hour and minute hands should be polished on the bevel and matte on the top surface. Cheap copies plate them one way and the effect dies in daylight.
Date alignment gets overlooked. The numeral should sit centered in the aperture, and the window edges should be cleanly cut.
Strap and clasp
Most examples ship on leather, and factory straps are usually the weakest part: stiff, thin, or shiny in the wrong way. Budget for a replacement from day one. If you buy a bracelet version, check the end links for rattle and make sure the clasp closes with a solid click instead of a nudge.
Price tiers
- Budget tier: right silhouette, rough dial print, chronograph that may not reset cleanly.
- Mid tier: better dial and hands, modified 7750, usable strap.
- Top tier: closest case thickness, sharp printing, decorated movement, and usually a wait per batch.
Inspection list before you accept the watch
- Wind it. The rotor should spin freely and the crown should feel geared, not gritty.
- Run the chronograph for ten minutes, then reset. Repeat three times.
- Watch the small seconds hand at 6 for stutter or skipping.
- Examine the dial under a lamp from an angle. Dust and wobble show up here.
- Measure thickness and lug width yourself rather than trusting the listing.
- Confirm the caseback engravings match the reference you were shown.
What to expect long term
A 7750-based watch needs servicing like any other mechanical movement, and many owners never bother, they just replace it. That is a fair trade at replica prices, but know it going in. Keep it away from strong magnets, skip swimming unless the gaskets have been tested, and store it somewhere dry.
Buy the seller more than the listing. Photos of the actual watch, a live video of the chronograph running, and a return policy matter more than any spec sheet.